Hot-air engine.



4 PATENTED JAN. 14. 1908. A. MAYR s J. WALLAUE.

HOT AIR ENGINE.

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ALPHONSE MAYR AND JOHN WALLACE, Ol" BOMBAY, INDIA.

HOT-AIR ENGINE.

Specification of Letters Patent.

Patented Jan. 14, 1908.

Application filed October 4. 1907. Serial Noi 395.948.

To all 'who-m 'it may concern:

Be it known that we, ALPHONSE Mara, a subject'of the Emperor of Austria,andJonN WALLACE, a subject of the Kino of England, both residing atBombay, in tlie Empire of lndia, have invented certain new and usefulImprovements in or Relating to Hot-Air Engines, of which theI followingis a specification.

The object of this invention is to increase the efficiency and working`economy of hot air engines, more especially such as are used to operateVentilating fans and for other light work.

An apparatus embodying the present inveiitioii comprises a hot airengine with two cylinders known respectively as the working and thedisplacer cylinder the latter being suspended over a source of heat.This cylinder is divided into an upper or cooling part, and lower orheating part, by means of a ring of non-conducting material which formspart of the cylinder and which retards the passage of heat from theheatin f to the cooling part of it. The workinfr cylinder is attached tothe displacer cylinder but at the junction a liner of slowheat-conducting material is interposed to retard the assage of heat between the cylinders. T e displacer piston is a closed hollow cylinder,having near the middle of its length a diaphragm of iioii-conductingmaterial` which separates it into two parts, and retards the passiigeol' heat from one to the other. This piston is connected by means ofiiston and connecting-rods to the crank shallt. The working cylinder hasii trunk-piston connected by means of a rod to a separate crank on thcend of the shaft. A suita )le air passage connects the two cyliiidersand the inclosed air circulates between them.

The displacer cylinder is suspended in a stand'or )illar containing alamp or other source of icat, and this stand is lined where required,with non-conductiiig material to prevent loss of heat by radiation. Theheat acts first on the lower end of thc displacer cylinder and thenpasses upwards around it in a flue to an annular space around thenonconducting ring, it then escapes into a chimncy which carries awaythe products of comhustion. This chimney may bc fitted with ii damper toregulate the draft or escape of s ent gases. A non-conductiiig coveringis paced around the upper art of' the displacer cylinder to arrest ticloss of lient,

which comes very slowly past the non-con ducting ring.

A convenient construction embodying thc invention will now bc described,by way ol' cxample, with relcrence to thc accompanying drawings, showinga central vertical section of the apparatus.

'llie two cylinders are placed side by sideand connected to a commoncrank shaft o. 'llie u per or coolinir part a, of the displiiccr cylinier is prolonged so as to carry the crank shaft and to its side isattached the working cylinder b, a passage q opening into the bottom ofthc latter cylinder making communication between them; an insulating)late uf" of heat-insulating material separating the cylinders at thepoint of communication. A flange o on the part a of the displacercylinder rests upon a sheet metal stand i., forming the base of themachine, and beneath this flange is a ring lf, of iion-conduct-ingmaterial which separates the hcatinir or lower part f, of the displacercylinder from the cooling part a. The connection between the two partsis made by means of bolts passing through the flanges i and a, whichreduce the metallic connection between the upper part a, and the lowerpartf, of the displacer cylinder; the latter being made prcfera ily of'copper. The escaping heat whi e traversing the annular passage aroundthe non-conducting riiig, iiiipiiiges against the horizontal flange a,3of the cooling part f1., and communicatcs to it the small amount of heatnecessary to prevent the air from becoming so cool that it cannot absorbits pro )er charge ol' heat during the short interval ol' exposure tothel hot surfaces at f.

'lhc displacer piston (l, is a closed cylinder of thin metal cut andjoined by a diaphragm e of carthenware or otlici non-conductinirmaterial, which breaks the metallic continuity of thepiston and retardsthe passage ol heat from )elow upwards. 'lhe disp acer piston il, andthe working piston i', are connected to their respectivecranksbycomiccting rods my and n, and the cooling part r1, of thcdisplacei cylinder is closed with ii nouconducting continir (1, toconserve thi` reduced amount of heat it receives from thel heating part.A lining h., of non-conducting material is fixed within the metal casingi., and surrounds the part f, of thc displaccr cylinder. [t is piercedat (1, by ii. sight holel covered with mica which allows the lhiinc ofthc. lamp r, to be seen. A plate s closes the bottom of the lining h,and has an orifice to admit the burner of the lamp 1'. There is thus acontinuous protected passage for the products of combustion from theflame along the bottom and .sides of the displacer cylinder f, throu fhthe annular chamber around the non-con uctin ring k, and out by thechimney y, by whic the products of combustion are conveyed away to asufficient distance. The damper t, serves to regulate the current of sent gases.

Tlrie inode of operation of the working and displacer pistons is that ofa closed hot air engine of similar construction. The effect of thespecial insulation is as follows z- The working charge of air is heatedbetween the lower part of the displacer cylinder and its piston and asthe non-conductors dividing the displacer cylinder and its piston retardthe u ward passage of the heat by conduction, t e temperature of thelower part of these members is increased and the air exposed to themreaches a higher tem erature and is more rapidly heated an expanded thanif these non-conductors were not used. In order to keep the upper partof the displacer cylinder and its piston cool the non-conducting ring inthe displacer cylinder and the diaphragm in the displacer piston are ofsuch a depth, and so p aced, that the hot lower part of the displacerpiston never rises beyond the non-conductin ring in the displacercylinder and the coo upper gart of the displacer piston never passeselow the rin The transmission of heat from the hot ower part of thedisplacer cylinder and iston to their upper arts is therefore re uced toa minimum.

he latter parts remain cool and take up and dissipate readily without awater jacket or radiators, the small amount of heatcontained in therising working air. When the engine is small, or the air about it iscold the radiation may require to be mitigate by a non-conductingcovering a around the cylinder a, to prevent it from becoming too coolfor efficient workin f. The invention is applicable equally when thecylinders are arallel or in line.

hat we claim as our invention and desire to secure by Letters Patentis 1. In a hot air engine a working cylinder and piston, a dis lacercylinder comprising a heating part am. a cooling part, and a heatinsulating part between the heating and cooling parts in combinationwith a displacer piston consisting of two parts separated by aninsulating section, substantially as set forth.

2. In a hot air engine a displacer cylinder comprising an upper coolingpart and a lower' metallic heating part and an intermediate heatinsulating portion separating the upper and lower metal portions incombination with a displacer piston consisting of upper and lower metalparts and a separating ieat insulating )art and a working cylinderconnected to t ie dis )lacer cylinder and a sepai rating insulatorbetween the two cylinders substantially as set forth.

3. In a hot air engine a working cylinder and piston, a dis )lacercylinder comprising a heating partand a cooling part, and a heatinsulating part between the heating and cooling parts, an insulatingcovering around the cooling part in combination with a displacer pistonconsisting of two parts separated by an insulating section,substantially as set forth.

4. In a hot air engine a displacer cylinder comprising an upper coolingpart and a lower metallic heal-ing part and an intermediate heatinsulating iortion separating the upper and lower inetai portions, aninsulating covering around the cooling part, in combination with adisplacer piston consisting of u )per and lower metal parts and aseparating wat insulating art and a working cylinder connected to t iedis lacer cylindler and a separating insulator iietween the twocylinders substantially as set forth.

5. A hot air engine comprising a displacer cylinder consisting of twometallic parts and an intermediate insulating part, a Histon in saidcylinder comprising two meta ic parts and aseparating intermediate heatinsulating part in combination with a working cylinder supported on theside of the dis lacer cylinder, insulatin plates between t e adjacentportions of t e working cylinderl and dis- 100 placer cylinder, and aheat insulating covermg about the up er end of the displacer cylindersubstantia ly as described.

6. A hot air engine comprising a displacer cylinder consisting of twometal ic parts and 105 an intermediate heat insulating part, a piston insaid cylinder comprising two metallic parts and a separatingintermediate heat insulating part in combination with a working cylindersupported on the side of the dis- 110 placer cylin er, insulating platesbetween the adjacent portions of the workingcylinder and displacercylinder, and a heat insulating covering about the upper end of thedisplacer cylinder, and an outlet for the products of 115 combustiona)proximatcly on a level with the heat insullating )ortion of thedisplacer cylinder, substantial y as described.

In testimony whereof' we have signed our names to this specification inthe presence of 12o two subscribing witnesses.

ALPHONSE MAYli. JOHN WALLACE.

Witnesses:

JAMsETY DUisnAw, W. C. Fan.

